Process of making bituminous emulsion



Patented Oct. 29, 1929 UNITED STATES PATENT OFFICE PROCESS OF MAKING BITUMINOUS EMULSION No Drawing. Original application filed January 17, 1921, Serial No. 438,050. Divided and this application filed May 25, 1925.

This application is a division of an application filed by me, Serial No. 438,050 on January 17th, 1921.

This invention relates to improvements in process of making bituminous emulsion and refers more particularly to aqueous bituminous emulsions in which the adhesive particles of bituminous or like substances are enveloped in a non-adhesive film or coating ren- 1o dering the emulsion non-adhesive.

coatings; to provide a process in which, by

means of the addition of a third substance, the clusters of non-adhesive particles sur rounding the adhesive material in the emul-.

sion are caused to, cling tenaciously to the adhesive substance, making the emulsion substantially more permanent in its character; to provide a rocess in which, during the combination 0 the emulsifying and adhesive substances, the surface of the emulsion is kept constantly covered by the emulsifying agent whereby the formation of oily or greasy particles is obviated, producing a non-adhesive emulsion; to provide a process in which, due v to theaddition of a third substance, which is slightly acid in character, the formation of the o l particles produced during emulsification is reduced materially, and in general,to provide a process of the character referred to.

In carying outcommercially the invention.

described in' Letters Patent No. 1,302,810 issued May 8th, 1919, and as supplemented by application Serial No. 27 4,497 filed February 1st, 1919, it has been the practice to produce a non-adhesive emulsion by dispersing ad- Serial No. 82,839.

hesive bituminous binders with an emulsifyin agent. such as colloidal clay in an aqueous ve c e.

the emulsion, after being made, was subjected to extreme dilution with water, I have found the insulating or protectingquality of the' clay particles could be effectively increased 1 by the use of a fixing agent which caused the clay to cling or cluster more tenaciously about the particles of bituminous material.

This function of the clay can be readil observed by microscopic examination 0 the emulsion, particularly with the use of stains such as malachite green which bring the clay particles into effective view. In other words,

the third substance acts as a flocculating agent. e

The formation of oily free particles in the emulsion, which seems to take place. to a greater extent upon the hot surface thereof,

wasobjectionable when it was desired to run the emulsion over a paper machine withfibrous stock or in other manufacturing uses when a maximum degree of non-adhesiveness was desired. From experimentation, it has been learned that a slight alkalinity of the clay promotes this oily condition of the emulsion. Lime in the clay will give like results and b adding alkali into the clay during emulsi cation, the tendency to produce oil particles is greatly accelerated.

o obviate this objectionable tendency, I

add a third substance, having a slightly acid reaction, and having the purposes of a floc culating agent, to the emulsifying agent in .7 its aqueous vehicle. Such substances as alusubsequent applications and particularly anmin m sulphate, sodium acid phosphate and others of a similar character supply elements to the emulsion which obviate the formation of these oily particles upon the surface of the emulsion during the mixing and, in addition, tend to cause the particles of emulsifying agent to cluster around the adhesive substance dispersed through the emulsion as before described. The addition of a third sub- ,stance, such as aluminum sulphate, to an amount of one to fifteen per cent of the emulsifying agent in the emulsion is satisfactory to produce these results. However, it is understood that the quantity and concentration of this third substance is susceptible of variation according to its character and may be regulated according to the quality of the emulsifying agent used and the character of the bituminous adhesive substance to be emulsified. In producing this emulsion, the emulsifying agent, which may be clay, is thoroughly mixed in an aqueousvehicle and the third substance, which, as described, ma aluminum sulphate, sodium acid phosp ate or numerous other materials having a slightly acid reaction or substances giving the above described results and not having the acid reaction, for example, of calcium chloride, is added to the aqueous suspension. This suspension is combined with the asphalt in a mixer in which there are large paddles kept constantly revolving to thoroughly disperse the bituminous substance through the emulsifying liquid. The construction of this mixer is of importance as one of the essential factors in the formation of the emulsion is that the surface of the emulsion must be kept at all times covered by the emulsifying agent which is added. While I am not exactly certain of the cause of this oily formation, its appearance, when the hot emulsion contacts with air, seems to indicate some influence of the air in promoting what appears to be a capillary fractionation of some of the asphaltic particles. It is this kee ing of the surface of the emulsion constant y covered in connection with the reagent used which reduces the formation of the oil particles during emulsification.

By placing the revolving paddles on a vertical shaft within an inner open-ended cylinder and causing a circulation of the emulsion downward through the inner cylinder and upward about the annular space between the inner and outer cylinder and simultaneously with this circulation adding the emulsifying agent inits aqueous vehicle to the outer circumference of the upper emulsion surface, the emulsifying agent is caused to flow inwardly with the emulsion completely covering its surface. During this operation the emulsion is in the form of a stiff paste and sluggish to accelerate during mixing. It may be mentioned. in this regard that the third substance added toassist in causin the non-adhesive particles of the emulsiing agent to more firmly envelo the adhesive particles of the bituminous su stances assists the emulsifying agent in reducing the formation of the oil particles on the surface of the emulsion, a factor which may be due to the character of the material itself or to the fact that it gives the emulsifying agent the tendency to cling to the adhesive particles and.v therefore, more completely protect those exposed on the surface during the initial mix- TVhile the efl'ect of the fixing agent'is substantially the same whether added before or after the formation of the emulsion in so far as clustering is concerned, if desired to reduce the oily formation, it is preferablyeadded with clay and water prior to emulsification;

I claim as my invention:

1. A process of formin an emulsion comprising dispersing an adhesive bituminoustype material in an aqueous medium containing a dispersion means, and adding a fluocculating agent to the dispersion means prior to the combination of the dispersion means in its aqueous vehicle with the bituminous-type material,'whereby to cause the particles of the dispersion means to more tenaciousl gather about the dispersed particles of hitumen.

2. A process of forming a non-adhesive emulsion comprising emulsifying an adhesive bituminous-type substance with an emulsifyin agent in an aqueous vehicle and adding a occulating agent having an acid reaction to the emulsifying agent in its aqueous" vehicle prior to its emulsification with the adhesive bituminous substance.

3. A process of forming an emulsion comprising emulsifyin a bituminous-type substance with a cla ike emulsifyingagent in an aqueous vehic e and adding a flocculating agent havin an acid reaction to the emulsifying agent 1n its aqueous vehicle prior to 1ts emulsification with the bituminous-type substance.

4. A process of forming an emulsion comprising dispersing asphalt inan aqueous vehicle containin a paste forming mineral powder and ad ing a flocculating agent having an acid reaction to said paste formrng mineral powder in its aqueous vehicle prior to its emulsification with the asphalt.

5. An emulsion comprising a water resistant material of the heat liquefiable dispersed in an aqueous vehicle containing an emulsifying a ent and a flocculating agent having an aci reaction and causing flocculating of the emulsion.

6. An emulsion comprising a water resistant materialof the heat liquefiable dispersed in an aqueous vehicle containingan emulsifying agent and a metallic salt having an acid reaction and capable of flocculating the emulsion.

7. A dispersion resistant to breaklng by substantial quantities of electrollytes comrising water-resistant materia of the itumen-pitch type dispersed in an aqueous vehicle containing a dispersing agent inert to electrolytes, and a flocculating agent in sulficientquantity to cause the dispersed particles to cluster about each other. 8. A dispersion inert toelectrol es comprising water-resistant material 0 the heat liquefiable bitumen-pitch type dis ersed in an aqueous'vehicle containing a ersing agent of the mineral owder type an a flocm culating agent in su cient quantlty to cause thfi dispersed particles to cluster about each ot er. 9. A dispersion comprisin water-resistant material of the heat lique able bitumenpitch type dispersed in an aqueous vehicle containing a dispersing agent and a flocculating agent in suflicient quantity to cause flocculation of the'dispersed particles but insufiicient to induce breaking of the dis- 2o persion.

LESTER KIRSCHBRAUN. 

